Overhead air filter

ABSTRACT

Incoming filtered air is discharged as a uniform down-current into a room from an array of horizontal filter units of generally pyramidal shape with a filter cell across the larger end, these units being either fitted individually into or out apertures in a false ceiling by connecting pieces at their apex, or connected side-by-side as a common duct by connecting pieces on their sloping sides.

United States Patent [1 1 Neumann et al.

[451 Sept. 25, 1973 OVERHEAD All! FILTER [75] Inventors: Gerhard MaxNeumann;

Hans-Joachim Wittemeier, both of Berlin, Germany [73] Assignee:Delbag-Luflfilter Geselllschaft mit Y beschrankter Haftung, Berlin,

Germany [22] Filed: Apr. 24, 1970 [21] Appl. No.1 31,674

[30] Foreign Application Priority Data 55/502, 504, 505, 507, 508, DlG.29; 98/33, 36, 40, 41; 285/368, 64, 177

3,465,666 /1969 Knab 98/33 3,522,724 8/1970 Knab 55/97 3,553,941 l/197lWittemeier et a1. 55/473 1,906,826 5/1933 Smith et a1 285/368 1,992,5032/1935 Penick et a1. 285/368 3,176,447 4/1965 Omohundro et a1 55/DIG. 293,280,541 10/1966 Soltis 55/484 3,308,741 3/1967 Chambers 98/40 D3,360,910 1/1968 Soltis 55/484 3,376,695 4/1968 Mackley 55/505 3,552,1041/1971 Wood 55/502 3,581,478 6/1971 Smith 55/484 PrimaryExaminer-Bernard Nozick Attorney-Karl F. Ross 57] ABSTRACT Incomingfiltered air is discharged as a uniform downcurrent into a room from anarray of horizontal filter units of generally pyramidal shape with afilter cell across the larger end, these units being either fittedindividually into or out apertures in a false ceiling by connectingpieces at their apex, or connected side-by-side [56] Referen e Cited asa common duct by connecting pieces on their slop- UNITED STATES PATENTSmg 3,314,353 4/1967 Knab 98/31 7 Claims, 9 Drawing Figures Fig. 6

Fig.9

lm en fan- OVERHEAD AIR FILTER FIELD OF THE INVENTION This inventionrelates to filters for separation of suspended material from air orother gas, preferably for ventilation of a room to be kept clean.

BACKGROUND OF THE INVENTION An earlier commonly assigned and co-pendingapplication Ser. No. 796,832 filed by Hans-Joachim Wittemeir and myselfon Feb. 1969 (now US. Pat..No. 3,553,941 of 12 Jan. 1971 describes anarray of filters wherein a transverse or descending air flow isprovided. The present invention relates also to the problem of providingsuch a descending flow'with the aid of a horizontal array of overheadfilter units, and particularly aims at facilitating the removal of allor part of any filter unit for purposes of replacement.

SUMMARY OF THE INVENTION In accordance with an important aspect of mypresent invention, the filter units disclosed in US. Pat. No. 3,553,941are supplied with air in parallel from an overlying plenum chamber whoselower wall is defined by a support for these units, specifically a plate(or a series of interconnected plates) forming a false ceiling below theoriginal ceiling of the room to be aerated. This support is providedwith several perforations, one for each unit, aligned with the narrowerupper end of the downwardly converging housing of the unit whose broaderlower erid terminates in a filter'cell as described in that patent. Theentire unit, or at least its filter cell, is detachably secured to thesupport by fastening means anchored on the one hand to the support andon the other hand to some part of the unit.

In a preferred embodiment, the upper end of the housing is upwardlyextended in the form of a neck clamped by the fastening means, throughthe intermediary of a deformable sealing element, to a sleeve integralwith the lower wall of the plenum chamber, i.e., with the false ceilingreferred to above. The neck may have an external peripheral shoulderengaged from below by a pressure member such as a clamping plate;advantageously, this shoulder is constituted by a collar integral withthe neck which forms an inner peripheral recess as a seat for the lowerend of the sleeve, the sealing element being then in the form of anannular strip resting on that seat. It is, however, also possible to letthe neck pass through the sleeve and the perforation; in that case thesealing element may have the form of a cuff with a first portion clampedto the neck and a second portion clamped to the sleeve, the latterportion being folded back in a specific instance around a third portionpassing between the neck and the surrounding sleeve. The neck could alsobe provided with a peripheral bead which clears the surrounding sleeveon being inserted into same from below, the bead then coming to rest ona jointing compound overlying a sealing strip wedged into theintervening space.

DESCRIPTION OF THE DRAWING The invention will be further described withreference to the accompanying drawing wherein:

FIG. 1 shows a diagram of a filter array formed in a ceiling by aplurality of housings equipped with filter cells;

FIG. 2 shows a housing with a sealing and fastening system situatedbelow the ceiling;

FIG. 3 shows a housing with a sealing and fastening SPECIFIC DESCRIPTIONAs shown in FIG. I, an intermediate or false ceiling 3 is suspendedbelow the original ceiling 1 of a work room with sidewalls 2. At thisintermediate or false ceiling 3 are situated four housings 4 in each ofwhich there is sealingly installed a filter cell 7. In the top of thehousing 4 opposite the filter cell 7 there is situated a connectingpiece or sleeve 5 which is sealingly received in a perforation 6 of thefalse ceiling 3. The air which is to be treated is passed by a duct 8through an opening 9 into a plenum chamber 10 above the false ceiling 3;it then flows through the open connecting pieces 5 into the housings 4and, after passing through the filter cells 7, into the work room 11which is to be ventilated.

A mounting of the connecting piece in the false ceiling 3 is shown inFIG. 2. The housing 4 receiving the filter cell 7 with interpositioningof a seal or gasket 18 possesses a connecting piece or neck 12 which onits extremity is bent outwardly to define an annular collar 13 in whichis situated a sealing ring 14 of resilient material. On the underside ofthe false ceiling 3 is fastened an annular stub or sleeve 15 surroundingthe perforation 6; clamping screws I7 are secured to the underside ofthe false ceiling 3. The connecting piece 12 has a clamping plate 16,engaging under the annular collar 13, which is lifted by tightening theclamping nuts 17 until the sealing ring I4 is in contact under pressurewith the lower edge of the annular stub 15. This ensures a hermeticconnection of the housing 4 and thus of the filter cell 7 with theplenum chamber 10 situated above the false ceiling 3 (see FIG. I), fromwhich the flow of gas or air to be treated passes, without infiltratingair into the room II which is to be kept clean, through the connectingpiece 12, the housing 4 and the filter cell 7. In the embodimentaccording to FIG. 2, the installation and replacement of the housing 4can be performed from the work room 11, i.e., from below.

FIG. 3 shows a modified embodiment. In this case, the housing 4 carryingthe filter cell 7 has a connecting piece or neck 19 which passes throughthe perforation 6 of the intermediate panel 3 and projects into theplenum chamber 10 thereabove. On the upper side of the intermediateceiling 3 is fastened a sleeve 20 which carries deformable a sealingcuff or sleeve 21. A bottom clamping ring or clip 22 is provided bymeans of which the lower extremity of the sealing sleeve 21 is clampedbetween the clip 22 and the pipe stub or inner sleeve 20. Above the clip22 I have arranged a second clip 23 which presses the upper extremity ofthe sealing sleeve against the outer periphery of the connecting piece19. The clip 23 is pulled down to seat on the lower clip 22 by theweight of the housing 4, so that the housing 4 is held in position. Ifit becomes necessary to replace the housing 4, the upper clip 23 isremoved whereupon the connecting piece 19 with the housing 4 and thefilter cell 7 can be pulled out downwardly through the perforation 6 ofthe false ceiling 3.

Clip 22 embraces a lower portion of cuff 21 to clasp it onto sleevewhereas clip 23 clamps a lower portion of the cuff to neck 19, so thatno air can come in directly through the perforation 6.

FIG. 4 shows different possibilities in the use of the housing 4 whichaccording to the illustration at the right is equipped with a filtercell 7, according to the illustration in the middle is equipped with agrill insert or anemostat 24 for the purpose of air distribution, andaccording to the illustration at the left is equipped with a closingshutter 25.

In FIG. 5, each filter-cell housing 4 is associated with a supportingunit comprising a carrying plate 26 deformed into a central anddownwardly directed annular sleeve 27. In size, the plate 26 correspondsto at least the greatest horizontal cross-sectional area of thefiltercell housing 4. An upwardly bent peripheral flange 28 thereof hasan inbent edge 29. When assembled, the carrying plates 26 form anintermediate or false ceiling,

the individual plates 26 being interconnected by mountings 30 arrangedin the ceiling 1 of the room. Each mounting 30 consists of two generallyparallel vertical plates whose short horizontal flanges 31 are bentparallel to the ceiling 1 and overlap one another. The lower edges ofthe fasteners 30 overlap the flanges or rims 28 of two adjacent plates26 and interconnect these by means of a sealed fastening screw 32. Inorder that this joint may be sealed in an airtight manner, a jointingcompound 33 is cast between the uppermost edges 29 which jointly definea V-shaped channel. As shown at the right-hand side of FIG. 5, themountings 30 may be attached to the original ceiling 1 of the room. Itis advantageous, however, that the mountings 30 be secured to theceiling 1 in a yertically and transversely displaceable manner, to allowprecise alignment of the individual plates 26 with formation of ahorizontal intermediate ceiling. To facilitate this, the ceiling 1 hasnuts 35 situated in it; countersunk nuts 35 are engageable from below bybolts 34. These bolts and nuts support the overlapping flanges 31 of themountings 30,

so that the individual mountings 30 are vertically adjustable byappropriately setting the screw bolts 34. To afford transversedisplaceability of the mountings 30, elongated slots 36 are provided inthe overlapping flanges 31. It is possible in this way, irrespective ofthe configuration of the ceiling 1, to position the individual plates 26as a horizontal false ceiling in which the individual carrying plates 26adjoin one another on all sides.

The peripheral web or sleeve 27 of the plate 26 embraces part of a sealor gasket constituted as a deformable sleeve or cuff 37 whose lowerextremity 38 is folded back to overlap the outer surface of the sleeve27 surrounding an intermediate portion of the cuff. A lower clip 39bears on the inverted extremity 38 of the sleeve 37 and seals off theannular web 27, so that no infiltrating air can issue from the plenumchamber 10 formed between the ceiling and the plates 26; an upper clip40 presses the sleeve 37 in fluidtight manner against the connectingpiece or neck 41 of the housing. The upper clip 40 simultaneously actsas a mounting for the connecting piece 41 whose upper end has an annularouter bead of increased diameter 42 which prevents a downwarddisplacement of the housing 4.

In FIG. 6 the central perforation of the plate 26 is formed with anintegral upwardly directed and conically widening peripheral sleeve 55.The smallest diameter of this sleeve 55 exceeds the outer diameter ofthe connecting piece or neck 41 of the housing 4 carrying the filtercell 7 so that a resilient deformable sealing ring 56 can be and wedgedin between the lower region of the annular sleeve 55 and the connectingpiece 41. The funnel-shaped annular clearance situated above the sealingring 56 is filled with a jointing compound 57 of suitable material whichis easily removable. The bead 42 at the end of the connecting piece 41bears on the mass of joining compound 57. If it is necessary to replacethe housing 4, the jointing compound 57 is removed, the sealing ring 56is withdrawn, and the housing 4 with the connecting piece 41 is pulledout downwardly through the sleeve 55.

In the embodiment of FIG. 7, the connecting pieces or necks 5 of thefilter-cell housings 4 are firmly received in the false ceiling 3. Thefilter cells 7 are releasably arranged in their housings 4 by virtue ofthe fact that they rest on perforated plates 44 whose size correspondsto at least the maximum perimeter of the filtercell housings 4. Thelower edges 45 of the housings 4 are engaged by tie rods or similarelements 43 whose free extremities bear upon the edges of the perforatedplates 44. The clamping elements 43 hold the filter cells 7 sealingly incontact with the housings 4, through the perforated plates 44. Toreplace a filter cell it is only necessary to free the tie rods 43 andto replace the inoperative filter cell by a new one.

In the embodiment according to FIGS. 8 and 9, adjoining filter-cellhousings 4 have laterally projecting connecting pieces 46 extendingcoaxially toward each other. These extend from two sidewalls thereof.The connecting pieces 46 of mutually adjacent housings 4 of a row ofhousings are firmly and sealingly interconnected by couplings 47 to forma pipe duct or manifold 48. The pipe duct 48 is fastened to the ceiling1 of the room by means of suspension elements 49, without the need for afalse ceiling. The flow of air or gas to be purified is fed to theindividual housings 4 of a row of housings, each coupling 47 between anytwo adjacent housings being provided with a nozzle insert 48 tapering-inthe direction of flow which ensures a uniform distribution of the airflow in the pipe duct 48 between the individual cell housings 4 and thusbetween the individual filter cells 7.

As in the form of embodiment according to FIG. 6, the filter cells areheld in sealing contact on their individual housings 4 by meansofclamping elements 43 acting through perforated plates 44. If it becomesnecessary to replace the filter cells, the same procedure is applied asin the embodiment according to FIG. 6.

An input filter 50, which is shown in FIG. 8 and FIG. 9, is situated inthe pipe duct 48 at a location upstream of the first filter-cell housing4. The input filter 50 consists of two symmetrical filter-cell housings4 equipped with connecting pieces 51. The cell housings 4 enclosebetween their larger ends a common filter cell 7, held in sealingcontact therewith by means of clamping elments 43 (shown as tum-buckles)which overlap the edges of the two housings 4. The connecting piece 51of one housing 4 is firmly secured to the pipe duct 48 by means of acoupling 52, whereas the connecting piece 51 of the other housing 4 isjoined to a duct 54 supplied by a fan, which is not illustrated, bymeans of bellows 53. If the cell 7 of the input filter 50 is to bereplaced, the clamping elements 43 are taken ofi so that one filter cellhousing can be displaced toward the right by utilizing the flexibilityof the bellows S3. The filter cell 7 can then be taken out from betweenthe two housings 4 and a new filter cell 7 inserted, whereupon theclamping elements 43 are placed in position again.

The incorporation of an input filter 50, which may for example beconstructed as a coarse filter, is advantageous in that it extends theservice life of the filter cells 7 whereby their replacement need onlybe undertaken at longer intervals.

I claim:

1. An assembly for admitting filtered air to a room having a ceiling,comprising:

an overhead support underneath said ceiling forming a lower wall of aplenum chamber connected to a supply of air under pressure, said wallbeing pro-,

vided with a perforation bounded by a depending sleeve;

a unit provided with a downwardly diverging housing terminating in afilter cell at its broader lower end, said housing being provided at itsnarrower upper end with an upwardly extending neck of substantially thesame inner diameter as said sleeve, said neck widening at its top into acollar embracing said sleeve; and

a plurality of fasteners depending from said wall and carrying clampingmeans releasably engaging a peripheral shoulder on the underside of saidcollar for detachably suspending said unit from said support withestablishment ofa flow path from said plenum chamber through said filtercell, said neck and said collar forming an airtight seal between saidwall and said housing.

2. An assembly as defined in claim 1 wherein said clamping meansincludes a pressure member surrounding said neck and bearing from belowupon said shoulder.

3. An assembly as defined in claim 1, further comprising a sealing stripclamped between said sleeve and said collar.

4. An assembly as defined in claim 1 wherein said wall forms part of afalse ceiling paralleling the ceiling of the room and defining saidplenum chamber therewith.

5. An assembly for admitting filtered air to a room having an originalceiling, comprising:

a false ceiling paralleling said original ceiling and defining therewitha plenum chamber connected with a supply of air under pressure, saidfalse ceiling being provided with a plurality of perforations eachbounded by a depending sleeve;

a plurality of units, one for each perforation, provided with adownwardly diverging housing terminating in a filter cell at its broaderlower end, said housing being provided at its narrower upper end with anupwardly extending neck aligned with and of substantially the same innerdiameter as a respective sleeve depending from said false ceiling, saidneck widening at its top into a collar embracing the aligned sleeve; and

individual fastening means for each unit anchored to said false ceilingand releasably engaging a peripheral shoulder on the underside of thecollar of the respective unit for enabling detachment of any unit fromsaid false ceiling.

6. An assembly as defined in claim 5, further comprising a deformablesealing element overlying said collar at its junction with said sleeve,said fastening means clamping said neck and said sleeve under pressureagainst said element.

7. An assembly as defined in claim 6 wherein said fastening meansinclude a pressure member surrounding said neck while bearing upon saidshoulder from below and bolts depending from said false ceiling inclamping engagement with said pressure member.

1. An assembly for admItting filtered air to a room having a ceiling,comprising: an overhead support underneath said ceiling forming a lowerwall of a plenum chamber connected to a supply of air under pressure,said wall being provided with a perforation bounded by a dependingsleeve; a unit provided with a downwardly diverging housing terminatingin a filter cell at its broader lower end, said housing being providedat its narrower upper end with an upwardly extending neck ofsubstantially the same inner diameter as said sleeve, said neck wideningat its top into a collar embracing said sleeve; and a plurality offasteners depending from said wall and carrying clamping meansreleasably engaging a peripheral shoulder on the underside of saidcollar for detachably suspending said unit from said support withestablishment of a flow path from said plenum chamber through saidfilter cell, said neck and said collar forming an airtight seal betweensaid wall and said housing.
 2. An assembly as defined in claim 1 whereinsaid clamping means includes a pressure member surrounding said neck andbearing from below upon said shoulder.
 3. An assembly as defined inclaim 1, further comprising a sealing strip clamped between said sleeveand said collar.
 4. An assembly as defined in claim 1 wherein said wallforms part of a false ceiling paralleling the ceiling of the room anddefining said plenum chamber therewith.
 5. An assembly for admittingfiltered air to a room having an original ceiling, comprising: a falseceiling paralleling said original ceiling and defining therewith aplenum chamber connected with a supply of air under pressure, said falseceiling being provided with a plurality of perforations each bounded bya depending sleeve; a plurality of units, one for each perforation,provided with a downwardly diverging housing terminating in a filtercell at its broader lower end, said housing being provided at itsnarrower upper end with an upwardly extending neck aligned with and ofsubstantially the same inner diameter as a respective sleeve dependingfrom said false ceiling, said neck widening at its top into a collarembracing the aligned sleeve; and individual fastening means for eachunit anchored to said false ceiling and releasably engaging a peripheralshoulder on the underside of the collar of the respective unit forenabling detachment of any unit from said false ceiling.
 6. An assemblyas defined in claim 5, further comprising a deformable sealing elementoverlying said collar at its junction with said sleeve, said fasteningmeans clamping said neck and said sleeve under pressure against saidelement.
 7. An assembly as defined in claim 6 wherein said fasteningmeans include a pressure member surrounding said neck while bearing uponsaid shoulder from below and bolts depending from said false ceiling inclamping engagement with said pressure member.